The field for the ATP Tour Finals will be completed by Dominic Thiem, who became the eighth player to qualify for the event.
Thiem clinched his position when both Tomas Berdych and Jo-Wilfried Tsonga exited the Paris Masters. Croatia's Marin Cilic was the seventh player to qualify, obtaining his spot during the week when he reached the semifinals.
This will be Thiem's first appearance in the tournament and he is only the second Austrian in history to make it to the event (the first was Thomas Muster).
"I'm so happy to have made it," Thiem said in a statement. "In the past two years [the Finals] became a goal and to achieve it at such a young age is amazing."
Gael Monfils will also be appearing in the Finals for the first time. Rafael Nadal, who was in the eighth position coming into the week, has said he will not be playing the tournament.
Novak Djokovic, Andy Murray, Stan Wawrinka, Milos Raonic and Kei Nishikori are the other players who have qualified for the ATP Tour Finals, although Raonic may also withdraw due to a right leg injury.